Electrical apparatus



Feb. 26, 1935. H. HMS 1,992,303

ELECTRI CAL APPARATUS Filed April 16, 1.934-

INVENTOR.

& Haro/d 77620 B AT RNEYT4-$ Patented Feb. 26, 1935 UNITED STATES PATENT OFFICE Aviation Corporation,

poration of New Jersey East Orange, N. 1., a cor- Application April 16, 1934, Serial No. 720,877

10 Claims.

This invention relates to electrical apparatus machines and particularly to means for regulating the out-put of dynamo-electric machines.

In automotive practice the generator, which is used to supply current for energization of the starting, lighting and other electrical equipment on the vehicle (automobile or aeroplane) is of course subject to the variable conditions characteristic of the operation of such vehicle and its propelling power plant and it has accordingly been customary to provide means for maintaining the electrical out-put, particularly the voltage of the generator, at a substantially constant value, notwithstanding the frequent variations in speed of the driving means for the generator and other variable factors as above suggested. One type of voltage regulator which has been used extensively involves the provision of an electro-magnetically actuated contact which serves to alternately insert in, and remove from the field circuit of the generator, a resistance unit which is in series with the field windings, thereby varying the strength of the generator field. When such a vibratory type of regulator is employed on an aeroplane having radio receiving or transmitting equipment, it sets up a disturbance which interferes with the proper receipt or transmission of radio signals, the disturbance beingglue to the inductive radiation caused by the rapid opening and closing of the field circuit as the regulating contacts vibrate at a very high frequency. It is evident therefore that it would be desirable first to avoid the necessity of such rapid making and breaking of the field circuit and secondly, to provide means for varying the strength of the field circuit by inserting in or removing from said circuit, a much smaller increment of resistance, thereby making it possible to correct a slight voltage variation without resorting to high frequency vibrations such as are required when. an entire resistance unit is rapidly inserted and removed as is in the type of vibratory regulator above described. It is therefore an object of the present invention to provide a voltage regulating system in which the resistance unit of the field circuit may be cut in or out by relatively small steps, the steps being of just suflicient number to correct the variation. By this means the frequency of vibrations is substantially reduced, and is therefore not so likely to constitute such a disturbing factor when used in association with radio equipment.

Other objects and advantages to be derived from the use of the invention lie in the specified construction inter-relation and method of operation of the elements entering into the invention as illustrated in one embodiment thereof which is shown in the accompanying drawing and described in the following specification. It will be understood however, that the drawing is merely 5 illustrative and is not intended to define the limits of the invention, reference being had for the latter purpose to the appended claims.

In the drawing the single feature is a schematic representation of the electrical circuits and parts 0 involved in the preferred embodiment of the invention.

Referring to the drawing, reference character 5 designates the generator whose voltage is to be controlled and the reference characters 6 and 7 5 designate the main output feeds from the generator leading to starting or lighting equipment or to a battery 3 and also the filament and plate circuit of radio tubes 4 in instances where the generator is used to supply energy for radio purposes. The field winding 8 of the generator is shown as connected in shunt with the armature winding by means of the leads 9 and 10, the latter including the movable arm 11 of a rheostat having a resistance coil 12 with which the arm 11 electrically connects and with one end of which the lead 13 electrically connects to complete the field circuit.

As above suggested, the invention contemplates the provision of means for moving the arm 11 along the resistance unit 12 by relatively small steps so as to vary the strength of the field circuit gradually and more flexibly than in the above described type of vibratory regulator of the prior art. As shown, such means includes a ratchet wheel 14 rotatable about a shaft 15 by the action of a reciprocating pawl 16 pivotally connected to the upper end of a rod or plunger 1'7 to which is connected a collar 18 cooperating with a compression spring 19, the function of which is to withdraw the pawl from engagement with the ratchet teeth upon deener gization of the electromagnetic coil 21- which surrounds the lower magnetizable end of the plunger 17. A detent 23 is pivotally mounted on a support 24 and is controlled in its movement by a tension spring 25 and a second electro-magnet 26 connected across the generator out-put lines 6 and 7, the purpose of the detent being to maintain the ratchet wheel against return movement to the normal position to which it is constantly urged by the provision of suitable means such as the spirally wound spring 29. A third electro-magnet 31 has a lead 32 connecting with line '7 of the generator circuit and the other lead 33 connects with the line 6 through an interposed switch 34, the contacts of which are separable upon descent of the plunger 17 from the position shown in Fig. 1 to the lower position to which it is urged by the spring 19. For this purpose one of the contacts of the switch 34 is mounted on a pivoted arm 36, the end 37 of which is in the path of the descending plunger 17, the said arm 36 being of such resilience that it automatically re-engages the switch 34 upon subsequent lifting of the plunger 17 by the re-energization of the coil 21. The coil 31 when energized attracts an armature 41 and thereby breaks the normally closed circuit passing through the leads 42 and 43 to the coil 21.

With the foregoing arrangement in mind, it will be seen that the operation of the voltage regulating system is as follows:

Assuming that it is desired to maintain the voltage across the lines 6 and 7 at a value of 14% volts, for example, the magnetic strength of relay 21 is so adjusted that the pawl 16 is raised to the wheel engaging position, and arm 11 oocupies a position substantially as shown, and the relays 26 and 31 have respective operating value somewhat below and above 14 volts. In the event that the voltage drops sufiiciently below 14 voltsfor example, to 13 voltsand assuring the relay 26 to be set for operation at 14 volts, both relays 21 and 26 would become deenergized sufficiently to permit spring 25 to withdraw the detent 23, and this in turn would permit the spring 29 to move the arm 11 in a counter clockwise direction, it being understood that the pawl 16 is at the same time moved to the lower or disengaged position by action of spring 19, which is now stronger than coil 21. The resultant removal of a slight amount of resistance from the generator field circuit will operate to restore the voltage across the lines 6 and '7 to the predetermined 14 volts, and it will be observed that this return is brought about without the necessity of any Opening or closing of switches whatever (except the switch 34, 36 which, under sub-normal voltage conditions such as are now being described, is of no significance).

If the voltage rises to 15 volts, for exampleassuming this to be the operating value of relay 31the resultant energization of the relay 31 will open the switch 41 and thereby again de-energize the relay 21. Thereupon the resultant descent of the plunger 17 and the opening of the switch 34 breaks the circuit to the coil 31, permitting a reclosing of the circuit to the coil 21 and a second lifting of the plunger 17 to carry the ratchet wheel one notch further in the clockwise direction and increase the resistance in the field circuit proportionately. This sequence will be repeated until arm 11 has moved a suificient number of steps to return the voltage of the generator to the predetermined 14% volts, at which value the switch 41 remains closed and the relay 21 remains energized, while the detent 23 also remains effective due to the continued energization of the coil 26. Only upon a drop of the voltage below 14 does the spring 25 operate to release the detent and to permit a return movement of the ratchet wheel, a roller brake 46 being provided, if desired, to retard the return movement of the wheel.

There is thus disclosed a combination of elements operative to achieve the objects of the invention as above suggested and possessing the advantages above outlined.

What is claimed is:

1. In combination with a generator and a rheostat for controlling the generator out-put, ratchet and pawl means for varying the setting of said rheostat step by step, from a given position to a new position, means energizable from said generator to move said ratchet and pawl, and means energizable from said generator to hold said ratchet and pawl in said new position.

2. In combination with a generator and a rheostat ior controlling the generator out-put, ratchet andpawl means for varying the setting of said rheostat step by step, from a given position to a new position, means energizable from said generator to move said ratchet and pawl and means energizable from said generator to hold said ratchet and pawl in said new position, and a third means energizable from said generator to render said ratchet moving means ineffective.

3. In combination with a generator and a rheostat for controlling the generator out-put, means energizable from said generator to vary the setting of said rheostat from a given position to a new position, and means energizable from said generator to hold the setting of said rheostat at said new position.

4. In combination with a generator and a rheostat ior controlling the generator out-put, means energizable from said generator to vary the setting of said rheostat from a given position to a new position, and means energizable from said generator to hold the setting of said rheostat at said new position, and a third means energizable from said generator to render said first named means incapable of energization from said generator.

5. In combination with a generator and a rheostat for controlling the generator out-put, ratchet and pawl means for varying the setting of said rheostat step by step, from a given position to a new position, means energizable from said generator to move said ratchet and pawl .and means energizable from said generator to hold said ratchet and pawl in said new position, and separate resilient means opposing the operation of each of said energizable means.

6. In combination with a generator and a rheostat for controlling the generator out-put, means energiz'able from said generator to vary the setting of said rheostat from a given position to a new position and means energizable from said generator to hold the setting of said rheostat at said new position, and separate resilient means opposing the operation of each of said energizable means.

'7. In combination with a generator and a rheostat for controlling the generator out-put, ratchet and pawl means for varying the setting of said rheostat step by step, from a given position to a new position, means energizable from said generator to move said ratchet and pawl, means energizable from said generator to hold said ratchet and pawl in said newposition, separate resilient means opposing the operation of each of said energizable means, and a third resilient means operative to cut all the resistance of said rheostat out of operation in response to a concurrent deenergization of both said energizable means.

8. In combination with a generator and'a rheostat i'or controlling the generator out-put, means energizable from said generator to vary the setting of said rheostat from a given position to a new position, means energizable from said generator to hold the setting of said rheostat at said new position, separate resilient means opposing the operation of each of said energizable means,

and a third resilient means operative to cut all the resistance 01 said rheostat out of operation in response to a concurrent de-energization of both said energizable means. v

9. In combination with a generator and a rheostat for controlling the generator out-put, ratchet and pawl means for varying the setting of said rheostat step by step, from a given position to a new position, 'means energizable from said generator to move said ratchetand pawl, means energizable from said generator to hold said ratchet and pawl in said new position, and a third means energizable from said generator to render said ratchet moving means ineffective, said three energizable means being constituted by three electro-magnetic devices having magnetizing potentialities responsive to difierent E. M. F. values of the current delivered by the generator.

10. In combination with a generator and a rheostat for controlling the generator out-put, means energizable from said generator to vary the setting of said rheostat from a given position to a new position, means energizable from said generator to hold the setting of said rheostat at said new position, and a third means energizable from said generator to render said first named means incapable of energization from said generator, said three energizable means being constituted by three electro-magnetic devices having magnetizing potentialities responsive to different E. M. F. values of the current delivered by the generator.

I HAROLD HAAS. 

